Quoted from DiscoDungeon:
We generally don't explain exactly what the exploit is because honestly, if very few people, or only one person, know about it then it can be still used.
All you're doing by hiding it is enabling people 'in the know' to abuse it freely without recourse from other players. If it's bad enough that you can't tell people about it, then those games shouldn't be used in any serious competition where money is involved, IMHO. I feel like players have a right to know if they're about to get dicked over on a game for a stupid reason. Yes, there are cases like Earthshaker and others where you can watch what the other players are doing and mimic that, but some of these setups, like the GOT "Hand of the King" scoring ridiculousness setup, are pretty complicated and someone walking up to a game for the 50th time might not even know about it. Especially on new games with known bugs...that crap should not be withheld. I'll never forget the time I was playing Junkyard with some guy and he got the hidden random multiball in there and I was just like WATAF?! Had no idea it was there and the guy played coy with me when I asked, so I went and googled it and found it out. It wasn't in a tournament, thankfully, but...yeah...I know the feeling.
One notable exception: Pinburgh..... that tournament represents, to me, the beauty of everything pinball. You never know what you're going to play, and if you were almost anywhere else in a public location, you'd likely be playing games that had questionable things going on with them. I think it's far more important for that tournament to represent all of pinball than to have a bunch of duplicated games, and players there are guaranteed a minimum of play. One questionable game shouldn't ruin an entire weekend, unless you're just determined to be #1 seed.
*Edit* There's also been at least one case of an exploit being brought to light that the 'in the know' players didn't want to share that Stern later fixed after it got blown out by a few people on here. If this stuff doesn't get reported, and talked about, will Stern care about fixing them? No.